What Happens When Mold Remediation Takes Place?

Mildew on Wall
Mildew on Wall. Getty / Vinod Kumar M / EyeEm

Exactly what happens when a mold remediation company shows up at your house to rid your house of mold?

An hour or two before the company is due to arrive, clear out access to the remediation zone.  Sequester house pets in a separate room put the dog in the backyard, move cars from the driveway or garage, and clear a wide access from the outside all the way to the mold area. 

Day 1: Kill Mold with Biocide

  • Company Prepares:  The mold remediation company will park a truck as near as possible to the doorway, lay down plastic sheeting, and run hoses through the house to the mold area. If the mold area is accessible from the outside (such as a crawlspace), so much the better. A good mold remediation company will take care to keep your house clean while they do the work.
  • Suiting-Up Process:  As with any other potentially hazardous process, such as the removal of lead-based paint or asbestos, mold remediation workers fully suit up for action: head-to-toe white suits, booties, respirators, and goggles.  This does not necessarily mean that the mold remediation company will be removing toxic mold. This is the usual procedure for any job they are dealing with.
  • Spray Down:  The first step of this two-step process is to spray the mold area with biocide. Biocide is an EPA-approved liquid which kills mold. Note that bleach is not approved by the EPA for killing mold. Typically, this first step should take less time than the second step.
  • Wait:  After the workers leave, the biocide goes to work, killing the mold spores.

Day 2: Spray Mold Area with Encapsulant

Next day, the mold remediation company returns. Again, clear access is needed.

  • Encapsulation:  The workers will spray the area with a type of paint or whitewash that encapsulates the remaining mold spores. The mold remediation company should spray well beyond the moldy area to ensure that no more mold grows. For example, if only a limited area of an attic exhibits mold, the company will probably still spray down the entire attic. This is more desirable, and you should confirm with the company that they will do this.